Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Control of US Senate at Stake Tuesday Katherine Gypson Control of the U.S. Senate -- and largely the success or failure of the next U.S. president's agenda -- rests on just a handful of races nationwide that polls show are tightening in the final hours before Election Day 2020. Of the 35 U.S. Senate seats up for reelection Tuesday, seven are rated true toss-up races by the non-partisan Cook Political Report. Democrats need a net pickup of three seats if Democratic presidential candidate Joe Biden wins the White House or a net pickup of four seats if U.S. President Donald Trump is reelected to a second term, because if there is a 50-50 Senate, the vice president breaks the tie. Senate Republicans currently hold a 53-47 majority but have a numerically more challenging year since they are defending twice as many seats as Democrats this election cycle. Only one of the 12 Democrat-held U.S. Senate seats up for reelection this year is rated as leaning Republican. In the Alabama Senate race, Trump-endorsed former football coach Tommy Tuberville has been leading Democratic Senator Doug Jones for months. Trump's influence will be the deciding factor for most of these close toss-up races, says Michele Swers, a professor of American government at Georgetown University. "If he wins a state, it's very likely that his coattails could help pull over the person who's running for Senate. And if he's doing poorly in a state, that's a big hurdle that they have to make up," she said. Here's where a handful of key races stand: Iowa "This is where you really get a good signal of the dynamics of the national race affecting state-level races," said Casey Burgat, director of the Legislative Affairs program at the George Washington University Graduate School of Political Management. .